Hungary's government will decide on Monday on legal steps to challenge a European Parliament ruling against the country for flouting democratic standards, Prime Minister Viktor Orban has said.

On Friday, Orban told state radio he expected a "serious legal debate" about the decision, Reuters news agency reported.

European Union legislators voted overwhelmingly in favour of launching a process that might lead to punitive action against the Hungarian government for flouting democratic rules on Wednesday.

The motion passed with 448 votes in favour, 197 against and 48 abstentions, marking the first time ever that the European legislature triggered an Article 7 procedure against an EU member state.

The Article 7 of the Treaty of the European Union, or TEU - which established the bloc in 1992 - seeks to protect the EU values defined in Article 2.

The unprecedented vote could allow Hungary's EU voting rights to be stripped. The issue will now be taken up another legislative body of the EU, the Council of Ministers.

In his Friday statement, Orban also criticised German Chancellor Angela Merkel, who on Thursday appealed to EU states to ensure the Frontex border agency had enough powers to help stop illegal migration, in line with European Commission plans.

"So the plan is that if Hungary cannot be forced to let in migrants, then it must be stripped of its right to protect its borders," Reuters quoted Orban as saying on state radio.

"They want to send mercenaries here from Brussels and take away this ... from our Hungarian sons ... who are protecting the borders. And we should not have any illusions, they will let in the migrants."

'Petty revenge'

Hungarian Foreign Minister Peter Szijjarto slammed the vote as "nothing less than the petty revenge of pro-immigration politicians".

"This decision condemning Hungary and the Hungarian people was made because we Hungarians have demonstrated that migration in not a necessary process and that migration can be stopped," Szijjarto told reporters in Budapest on Wednesday.

Since sweeping to power in 2010, Orban has pressured courts, media, and non-governmental groups, as well as refusing to take in asylum seekers arriving in Europe.

In June, Hungary's parliament overwhelmingly passed a law imposing jail terms for anybody seen to be aiding undocumented immigrants.